Posted
by
CowboyNeal
on Thursday May 25, 2006 @09:12PM
from the thanks-to-the-romulans dept.

Robotron23 writes "The BBC is reporting that a plan for a cloaking device has been unveiled. The design is pioneered by Professor Sir John Pendry's team of scientists from the US and Britain. Proof of the ability of his invention could be ready in just 18 months time using radar testing. The method revolves around certain materials making light "flow" around the given object like water."

sure this does preclude some applications, but imagine as a camouflage for an armored vehicle. you just keep the window visible and/or camera lens. you just got yourself a nice nearly invisible tank, which is a thousand time better than what they have right now

There are thousands of CCD "spy"cameras available everywhere that have an aperture of less than 3mm. Their video quality is not much worse than the regular surveillance cam, which is already enough for driving a tank. And I'm sure the military can do MUCH better than that.

An enemy near enough to see two tiny camera pinholes in front of a cloaked M1 Abrams from the future should make his peace with God immediately.

I don't know why everybody's so excited about cloaking devices. We clearly won't use them because you can't fire weapons when they're engaged and a clever chief engineer or science officer can always figure out a way to detect the ship anyway. On the rare occasion when we actually NEED a cloaked ship, like when we need to go back in time and pick up some whales, we'll just lift a Klingon ship.

AP Wire (2019): In the news today, once again the military claims to have "lost" an F-22 somewhere on the grounds of Andrews Airforce Base (AFB). Said Captain J. Andrews (no relation): "I could have sworn I parked the thing right over there. Last night's storm must have blown the locator-ribbon off the nose or something."

There is a Japanese research group which has a cloaking system (well, technically its more of a very adaptive camoflague -- significant drawbacks, such as the requirement to have a camera focused on the object you want to cloak, make it less than useful for military applications). Its essentially useless currently, but it makes for very fun tech demos.

such as the requirement to have a camera focused on the object you want to cloak, make it less than useful for military applications).

The US is used to enjoying air superiority, but other militaries might be interested in having an "instant camouflage screen" based on this idea over parked vehicles instead of messing around with nets and paint.

Maybe the Dutch/German Fennek [army-technology.com] vehicle can be adapted to sort of cloak itself from planes using its periscope.

No, for example, every inch of body armour may have a 2mm by 2mm (or smaller - nano) camera lense, and the rest taken up by some kind of 'screen' (but each screen is connected to a camera on the opposite side), and this is done all over the suit. Every 1 inch screen has its own camera on the opposite side. So from every angle, you would see what the cameras are recording on the exact opposite side (the camera is filming what you would have in your line of sight if the target was not standing in the way).

This would work great if you wanted to cloak a sphere. If, however, you view anything else, then as the viewing angle changes, so does what you expect to see behind it. Imagine (as a simple example) a cube with a large camera on one end and a screen on the other. You will only see what you expect to see when you view the screen straight on. Otherwise, the camera will have rotated with respect to you and will be transmitting diagonally to the screen.
Further, if you then deform the screen or the surface wit

I'd like to point out that this is brilliantly advanced... in theory. It's completely possible and will likely be buildable... in theory.

I RTFA, and frankly, it sounds like confirmation of the idea that mathamatics in general is WAY ahead of the other sciences. Things that are perfectly possible in theory are out of our grasp in the real world... right now, at least.

Even as a mathmatician, the fact that there's so much theory and so little actual DOING has me worried. There's a tiny flaw in the use of 'metamaterials' to make objects invisible... we don't HAVE metamaterials.

Well, I think that idea is that instead of just blindling pursuing random, poke-in-the-dark type science (Radioactivity & Marie Curie, anyone?), we theorize a possibility first, and then pursue long term, expensive projects to try and acheive it.Even if the project merely proves that implementation is practically impossible, the spinoffs can be valuable.

Given that mankind is not (at this moment) capable of vast scientific leaps into the future, evolutionary improvements via theorizing seems like a valid

I RTFA, and frankly, it sounds like confirmation of the idea that mathamatics in general is WAY ahead of the other sciences.

The thing you need to understand is that mathematics isn't a science. You can create lots and lots of perfectly valid mathematical theories, prove them true, and they don't have one tiny bit of them relevent to the real physical world. A great example of this is being able to cut a sphere in a certain way into an infinite amount of pieces, and reassemble it into a larger volume. It works great as far as the mathematics is concerned. But obviously you can't do that in the real world because real matter can't be infintely divided.

That's not to say that mathematics isn't usefull. Obviously it's used all the time to make models and predictions. My point is that there's no such thing as mathematics being way ahead of the other science, since mathematics doesn't really relate to the other science directly. As far as science is concerned, mathematics is just another tool in exploring science.

I RTFA, and frankly, it sounds like confirmation of the idea that mathamatics in general is WAY ahead of the other sciences. Things that are perfectly possible in theory are out of our grasp in the real world... right now, at least.

I fail to see the problem. The authors calculate the exact distribution of refraction indeces (they would have to vary) the cloak would have to have in order to work. They leave it to someone else to make a material with these properties. This distribution of labor is extreme

If you thinks mathematics is advanced, just wait until you learn about literature. Now there is a field where they are pushing the boundries. Why I once saw this sentence which described a technology beyond my wildest dreams, I am just really frustrated by how slow the physicists have been in implementing it.

If you thinks mathematics is advanced, just wait until you learn about literature. Now there is a field where they are pushing the boundries. Why I once saw this sentence which described a technology beyond my wildest dreams, I am just really frustrated by how slow the physicists have been in implementing it.

They claim that certain "metamolecules" have the power to make light behave like water, and flow rather than scatter. I quote:

"A little way downstream, you'd never know that you'd put a pencil in the water - it's flowing smoothly again.

"Light doesn't do that of course, it hits the pencil and scatters. So you want to put a coating around the pencil that allows light to flow around it like water, in a nice, curved way."

The truth is, water scatters when hitting something, too. It just doesn't *matter*, because all particles of water look the same to us. So, if the water particle that would have been in the middle without the disruption ends up on the far right, it doesn't matter!

However, we are very, very good at telling different pieces of light apart. At best, this will provide very good camo, where pieces of color from the environment behind you show up on you instead. At worst, the disruption from light working in unexpected ways will make this "invisibility" be a very noticeable beacon. You know how your eyes always flick to something that moves (animated ads, anyone?) This would be like that.

"What you're trying to do is guide light around an object, but the art is to bend it such that it leaves the object in precisely the same way that it initially hits it. You have the illusion that there is nothing there"

I get that. And I don't know enough physics say that it's definitely impossble for magic molecules to do this. However, the analogy they make is blatantly incorrect, so it doesn't lend confidence to their theory.We all know about the state of science reporting, though, so it's entirely possible the scientists are on the right track, and just the journalism was bad.

I actually think something like invisibility can be done someday, but it will involve electronics and computation. Instead of letting light pa

#1, that is certainly not how water flows over something.#2, how would you possibly account for the disrupted space? Wouldn't any human with good depth perception be able to tell that the "invisible" object is there simply by noticing that a piece of light is recessed? Sure, you could use this to walk across a desert with few interuptions, but in the more likely environments (urban landscapes and jungles) simply standing under a tree would give you away. The tree would appear to be split at the height of

Yeah, but the idea is that at any reasonable distance, observers wouldn't notice. Indeed, this is the idea behind all camouflage. And even if the light did appear to come from a slightly different place, it would still be better than the current system of "little splotches of color that might have some hues in common with the area we are fighting in."Of course, if the light, like the article claims, would appear to come from the same angle and position as if no object had interferred, then there would be no

At best, this would provide almost perfect camouflage. Bits of colour from the background would not show up on you; from whatever direction you look at it, you would see right through it. The light goes around the cloaked object, but there is no way for you to know that.

Of course, this only works over a restricted frequency range. In addition, since these metamaterials are usually based on resonant systems and are consequently strongly disp

Using the freedom of design that metamaterials provide, we show how electromagnetic fields can be redirected at will and propose a design strategy. The conserved fields--electric displacement field D, magnetic induction field B, and Poynting vector S--are all displaced in a consistent manner. A simple illustration is given of the cloaking of a proscribed volume of space to exclude completely all electromagnetic fields. Our work has relevance to exotic lens design and to the cloaking of objects from electromagnetic fields.

An invisibility device should guide light around an object as if nothing were there, regardless of where the light comes from. Ideal invisibility devices are impossible due to the wave nature of light. This paper develops a general recipe for the design of media that create perfect invisibility within the accuracy of geometrical optics. The imperfections of invisibility can be made arbitrarily small to hide objects that are much larger than the wavelength. Using modern metamaterials, practical demonstrations of such devices may be possible. The method developed here can be also applied to escape detection by other electromagnetic waves or sound.

Okay, I'm a dumb-butt bumpkin, so please excuse this if it's an idiotic question. But do these little blurbs hint at the idea that we could one day generate Voyager'esque holograms this way? I.e. using electro-magnetic fields to guide light and form an image?

this device is going to create smudges and blurs everywhere. As water flows around an object it is also stired, imagine a suspension in the water as it flows, the particles in the suspension will not come back in the same order and place. I imagine the cloaked object will be the right basic color - perhaps with a bit of a shift or blend, possibly with some resemblance to what's behind it, but overall I forsee a blur. Predators cloak is excelent in comparison to this tech and you can see that bastard. I

Reading TFA, it strikes me as being similar to something posted on/. a month or two ago promising the same thing. TFA is light on details, but if I remember the previous article correctly and they're a similar principle (that's a lot of ifs), then this is only useful for objects about the size of the wavelength of light being used. In other words, objects smaller than 3cm for microwaves, objects about a meter for radio, and about 500 nanometers for visible. That being said, it's useless for military applications since most military vehicles are larger than 1 meter. It's also useless for people since you'd have to be about a thousand times smaller than the width of a human hair in order to hide.

You'll note the picture in the article shows light rays hitting the object "head-on". What happens to rays that hit at an angle? Even if they exit at the same angle, are they exiting along the same axis, or displaced? The article doesnt say.

Also most substances have significant reflection at each air-substance boundary-- how will this device handle that issue?

Nice try, but still quite a long way from making an object "invisible".

Since the cloaking device will send all light around you to come out on your opposite side, you will not be able to see anything of the outside world while you are using it (I am not making this up, I RTFP in Science).
Sorry if this is will hinder your sinister plans.
Tor

Yes, in UK and Australia (and probably other Commonwealth nations, although I don't have personal experience outside of those two -- Canada I think follows American usage) "mathematics" always shortens to "maths" when describing a field of study ("My worst subject at uni was maths"), the process of computation ("Help me, I can't get the maths to work out here"), etc etc.

I would think a little different.. the Stealth Bomber is "Stealth" against active radar.. but can still be seen via passive radar..

abet harder to set up a passive radar system but not imposable..

when you send out the radar wave and look for what bounces back that is active.. when you have something on the other side of your target looking for that wave - that is passive.

if you setup two towers and the broadcast to each other and you fly between them they can tell even if they can see it actively... if you set up a perimeter of them say 3-4-5 or more and they all talk back and forth.. they could see the stealth bomber fly through and if your field is dense enough they would be able to track it easily

with this type of tech the item would be invisible to active and passive radar.. although I bet it would show some type of ghosting effect for areas near it via passive scan.. it would be very hard to track.

The Stealth bomber reflects the signals in all sorts of directions so there is a Mimimum radar return, some of those signals would be reflected to continue on to a reciever on the other end as in your example. However the return (on either end) would be weak sort of like a large bird or a SMALL plane. Sorting out whether that was a bird, small plane, a decoy, jamming, or a real B2 before a HARM missle from the B2 or a UAV blows you to bits is the problem. During the Gulf War the Iraqis were afraid to turn o

I have an idea for a super-cooled heat sink: how about a Nitrogen/Oxygen/CO2 mixture with an ambient temperature of -60&degF to -40&degF? Will that work? Of course that fluid would be rushing past at MACH2-MACH4, negating the cooling effect to some degree (er, no pun intended) but still. . .;)Seriously though, there are bigger heat signatures to worry about than the RF's conversion to heat, namely, the heat generated by moving through the air at supersonic speeds, and the exhaust gases. They have s

Sure. Too bad most RADAR systems are tuned to look for objects the size of planes and not birds.

Imagine retuning your RADAR for small objects; every bullet in the sky, every missile, every plane, and at least some atmospherics would light up like the Fourth of July. Now, it'd be possible if you have a very complex RADAR system with a computer attached that aided in target acquisition, but even designing a system that sophisticated to take out one class of aircraft will likely blow your defense budget tha

Craft like the stealth bomber work by scattering radar signals so they return almost any which way but back to the sender, making them appear a lot smaller than they really are. If there were something in the shadow of its profile, you wouldn't see that either. You would get no significant "ping" from your radar signal.

This theory, if it works and proves practical, would change things so you would get no reflection off the bomber, but you would see the object behind it just the same as if the cr

or the plane could listen to signals (ones it doesn't bend) just like a sub listens to other subs and natural sounds in water.. and can map the enviornment from that - there by flying via pasive scanning.. subs do it all the time.. but then again they don't have nearly as much to worrie about as planes..

I've read this story on about 4 news sites now and if I hear one more bloody site telling the public that this is 'Harry Potter' inspired I am going to have to cloak my foot up their asses. The mere thought of a scientist being inspired by Harry Potter pisses me off enough, but that they are perpetuating the idea that a childrens book written relatively recently is superceeding 150 years of SCIENCE fiction is what inspires stuff like this.